Meter station piping installation configuration is one of a number of effects that may adversely affect meter accuracy. Some piping configurations can distort the flow stream and produce flow measurement bias errors (i.e., offsets in the meter output) of up to several percent of reading. Valves, elbows, or tees placed upstream of a flow meter are just some of the piping elements that can distort the flow stream. In this paper, installation effects are discussed with respect to two of the four main components of a flow measurement system: the meter, or primary element, and the secondary (pressure and temperature) instrumentation. The effect of the velocity profile of the flow stream on orifice, ultrasonic, and turbine flow meters is discussed next. Installation conditions that may adversely impact the accuracy of pressure and temperature measurements are discussed after that. The gas chromatograph and the flow computer, the third and fourth components, are treated in separate courses